whats the point of those circle things under bottle caps?

Question

you know those clear plastic circles under the soda bottle caps, what are they for?

Answer 1

they keep the caps secure till the caps are opened. these circles are attached to the cap a little tighter than the cap. when you twist the cap to open these rings are detached and they achieve their size of the cap. be carefulto detach these rings because they can accumulate bacteria, if you are re-using the bottle for some other purposes.

Answer 2

They are probably there because in the old days the bottle caps could rust if they came in contact with the soda. Plus if the soda was corrosive enough (fizzy) it could eat at the bottle cap, giving the soda a metallic taste. I remember years ago when my dad made homemade root beer he made sure the bottle caps had those liners in them.

Answer 3

They seal the cap against the bottle so the gas will stay in and bad things stay out.

Answer 4

So you can tell if the bottle has been opened. If the cap has been separated from the circle then the drink has been opened. It is a safety feature to protect us from tampering..

Answer 5

To keep the soda from spilling out when tipped over. Since it's rubber it creates an airtight seal when screwed on tightly. Without the o-ring it'd come loose too often, wouldn't keep the carbonation, etc etc.

Answer 6

To seal the bottle

Answer 7

They help to create a suction for a better seal

Answer 8

They help seal the drink inside.

Answer 9

to keep the bottles from leaking. its a seal.